SANCHO uses finite strain constitutive theories for plasticity, volumetric plasticity, and metallic creep behavior. A constant bulk strain, bilinear displacement isoparametric finite element is employed for the spatial discretization. The solution strategy used to generate the sequence of equilibrium solutions is a self-adaptive dynamic relaxation scheme which is based on explicit central difference pseudo-time integration and artificial damping. A master-slave algorithm for sliding interfaces is also implemented.

The running time is dependent upon the size and complexity of the problem. SANCHO is not vectorized for the Cray. Sample problems EXAMPLE1 and EXAMPLE3 each ran in about 3 seconds, FRICTION in 44 seconds, and SPIN in 7 seconds on a Cray1S.

NESC9603/01

NEA-DB ran the test cases included in this package on a CRAY-XMP/2800 computer. Execution times varied between 6 and 24 seconds.

The program can control the addition or deletion of memory to and from blank COMMON. Memory is adjusted according to the size of the problem being executed. The memory adjustment feature may be eliminated by setting the size of blank COMMON array A in the main program equal to or greater than that needed for the solution and commenting out the calls to the memory adjustment routines. The memory adjusting routines may be appended to the SANCHO source or loaded as a separate library.

SANCHO does not contain a mesh generator but instead relies upon externally generated nodal and element data. The mesh-generating program QMESH,RENUM (NESC0612) can be used to generate mesh input. QMESH provides nodal coordinate data, element connectivity, and boundary flag identifiers for use in computing element stiffnesses, for applied loads, and for assigning boundary conditions.

SANCHO
calls system-dependent routines SECOND, CLOCK, and DATE, wich return the number of elapsed CPU seconds, time of day, and data, respectively. These routines can be eliminated if necessary or suitable alternatives supplied for the environment in which the program is being executed. SANCHO is designed to write a data file which can be used by various plotting routines for graphical post- processing of the data. The capability to write a restart file is also provided.